While looking for life on planets beyond our own solar system, a group of international scientists has created a colorful catalog containing reflection signatures of Earth life forms that might be found on ...

NASA's Kepler Space Telescope, despite being hobbled by the loss of critical guidance systems, has discovered a star with three planets only slightly larger than Earth. The outermost planet orbits in the ...

UC Berkeley and University of Hawaii astronomers analyzed all four years of Kepler data in search of Earth-size planets in the habitable zones of sun-like stars, and then rigorously tested how many planets ...

Researchers searching the galaxy for planets that could pass the litmus test of sustaining water-based life must find whether those planets fall in a habitable zone, where they could be capable of having ...

(Phys.org)—A joint effort of citizen scientists and professional astronomers has led to the first reported case of a planet orbiting twin suns that in turn is orbited by a second distant pair of stars.

(PhysOrg.com) -- In the last few years astronomers have observed that in some extrasolar systems the star is spinning one way and the planet, a "hot Jupiter," is orbiting the star in the opposite direction. ...

Mercury has an oddball orbit—it takes longer for it to rotate on its axis and complete a day than it takes to orbit the sun and complete a year. Now, researchers suggest photosynthesis could take place ...

(Phys.org) —Justin Crepp, the Freimann Assistant Professor of Physics at the University of Notre Dame, has published a study Thursday (Nov. 13) in the journal Science that details how next-generation planet ...

California Institute of Technology (Caltech) astronomers using data gathered at the W. M. Keck Observatory have developed a new technique for planetary scientists that could provide insight into how many ...

Orbiting the Earth 353 miles above the ground, the Hubble Space Telescope silently pivots toward its new target. At the same time, flying 93 million miles away in interplanetary space, NASA's Spitzer Space ...

Scientists at the Naval Research Laboratory (NRL) are part of a research team that has detected water vapor in the atmosphere of a planet outside our solar system. The team, including scientists from California ...

The Gemini Planet Imager (GPI) was built for one purpose: imaging extrasolar planets. In the seven months since it came online, GPI is proving to be an order-of-magnitude improvement-so much so that it may ...

Life as we know it on Earth is linked to our star, the Sun, which provides our planet with just the right amount of heat and energy for liquid water to be stable in our lakes, rivers and oceans. However, ...

Extrasolar planet

An extrasolar planet, or exoplanet, is a planet beyond our Solar System, orbiting a star other than our Sun. As of June 2009[update], 353 exoplanets are listed in the Extrasolar Planets Encyclopaedia. The vast majority have been detected through radial velocity observations and other indirect methods rather than actual imaging. Most announced exoplanets are massive gas giant planets thought to resemble Jupiter, but this is a selection effect (bias) due to limitations in detection technology. Projections based on recent detections of much smaller worlds suggest that lightweight, rocky planets will eventually be found to outnumber extrasolar gas giants.

Extrasolar planets became a subject of scientific investigation in the mid-19th century. Many astronomers supposed that such planets existed, but they had no way of knowing how common they were or how similar they might be to the planets of our Solar System. The first confirmed radial velocity detection was made in 1995, revealing a gas giant planet in a four-day orbit around the nearby G-type star 51 Pegasi. The frequency of detections has tended to increase on an annual basis since then. It is estimated that at least 10% of sun-like stars have planets, and the true proportion may be much higher. The discovery of extrasolar planets sharpens the question of whether some might support extraterrestrial life.

Currently Gliese 581 d, the fourth planet of the red dwarf star Gliese 581 (approximately 20 light years from Earth), appears to be the best example yet discovered of a possible terrestrial exoplanet that orbits within the habitable zone surrounding its star. Although initial measurements suggested that Gliese 581 d resided outside the so-called "Goldilocks Zone", additional measurements place it firmly within.